Date: Thu, 7 Jul 2005 07:46:46 -0400
Reply-To: John Wallace <jwallace@MSAD43.ORG>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: John Wallace <jwallace@MSAD43.ORG>
Subject: Re: HOW DO I CHANGE TPS?
In-Reply-To: <7b2855189c73b682346a2d28850afb6c@nventure.com>
Content-Type: text/plain; charset=ISO-8859-1
Barrett Willet <barrettw@nventure.com> writes:
>Just went through the same thing on my '88 Wolfsburg. Your switch may
>only need to be adjusted instead of replaced.
>Couple of places to start
>1) List archives: Lots of info on the archives
>2) GoWesty has a nice simple right up on checking TPS under their
>Technical section.
>
>BTW what steered you to a bad TPS switch?
>
>Barrett Willet
>'88 Wolfsburg
>
Dear Barrett,
Every once in a while over the last 6 months she'd start and warm up well
but then she'd buck and when I hit the accelerator to get her going she'd
hog up...then after a few minutes she'd come out of it.
then on an out of town trip after about 15 miles she started doing it
again. If I turned off the ignition and then restarted she'd go fine for
about a minute then go back into the hogging up and would eventually die.
Checked the ohms resistance across the 4 contacts on the AFM and they
appeared to be within range accoding to Haynes manual. Then checked the
resistance on the temp II sensor and that was a little weird...so I
replaced that. Didn't do it. Unhooked the O2 sensor and that didn't do
any thing.
I did open the top of the AFM and changed the dial that sets the spring
tension. (I marked the orig setting). After a stumbling start each time
(some balck smoke) for about 30 seconds, it comes out of it and runs well.
Even with this it is getting poor gas mileage.
When I was trying to find out the problem and settings were all orig, as i
would work the trottle at the engine bay, I would hear a snap/pop/click
type noise...not sure what that was but might be related to the TPS.
My hypothesis is that when I put all the settings back to original, when
the van warms up or is warm and first starts the system runs well meaning
that the ignition is fine, but when it warms up something is telling the
AFM that it is not warm and the AFM does not open enough to let the needed
air in.
One list member suggested that the carbon track in the air flow meter was
worn and not making good contact through the range...it does have grooves
in the carbon, but I'm not sure just how to adjust the swing of the
contacts.
I have searched the archives, but will look again to see what else I can
find.
Thanks for your help...it's greatly appreciated.
John
